DMTH4
LECTROSONICS, INC.
8
General Overview
The DMTH4 integrates telephone lines, video codecs
and external audio sources into the digital bus structure
of DM Series processors, allowing these audio signal
sources to operate as though they are another micro-
phone or audio input in the local sound system. This is
a complete DM Series digital matrix processor, with a
3-in/24-out digital matrix, automatic mixing and compre-
hensive signal processing on every input and output.
The latest generation DSP microchips and microproces-
sors are the core of the engineering of the DM Series
and the DMTH4 is no different. The focus and purpose
is to meet the requirements of modern applications and
also the demands for convenience and automation.
The DMTH4 is configured through the DMTH4 Control
Panel which is part of LecNet2™, a user-friendly, yet
powerful control program. The Control Panel offers
quick configuration and full command of the system
through either a USB or RS-232 compatible interface.
Once configured, it operates independently.
All models in the DM Series offer the same signal pro-
cessing functions, and vary only by the number of audio
inputs and outputs available. The DM’s basic structure
consists of three stages: Input, Matrix and Output. (See
DMTH4 Signal Flow Block Diagram
and
DMTH4 Func-
tional Block Diagram
.)
Each input channel includes a high quality 24-bit A-D
converter. Extensive digital signal processing is pro-
vided on each input channel. Each input channel is
processed and filtered as needed and the signal is deliv-
ered into the matrix.
The digital matrix mixer distributes each input signal
to any selected combination of mix busses, with level
control at each crosspoint. The matrix processes the
signals and communicates them to other devices in the
system. Each output receives signals from the mixing
matrix, the pink noise generator or the tone generator
as needed for setup, diagnostics or operation. Each of
the 3 outputs includes extensive signal processing to
optimize the mixed signal for the intended purpose, such
as sound reinforcement, recording or teleconferencing.
The DMTH4 is integrated into a system of DM Series
automixers using the Digital Audio Network Interface
(DANI). DANI connects the digital audio outputs of the
units through standard RJ45 connectors.
When DM Series automixers are stacked, mixing data
and the digital audio are passed between the slave units
and the master unit through the DANI. Multiple units can
be stacked in a master/slave configuration to expand the
number of inputs to hundreds of channels. The DMTH4
is designed to be the end slave unit of a DM Series
stack.
The audio and data from all units in the stack is gath-
ered in the matrix in the master unit, which is where the
final mix signals are generated. The first 12 final mix
signals from the master are back propagated through
the DANI to each slave. (See
DM Series Back Propaga-
tion Diagram
.)
DMTH4 Signal Flow Diagram
3 by 24
Automatic
Mixing
Matrix
Aux
Input
Processing
TEL
Input
Processing
Codec
Output
Processing
Tone
Generator
1 kHz, 0 dBu
Pink Noise
Generator
0 dBu
Codec
Input
Processing
24 Output Submixes
2 Expansion Submixes
26 Automixing Aux. Data
2 Expansion Signals
26 Automixing Control Data
24 Output Submixes
12 Backpropogated Final Mixes
2 Expansion Submixes
26 Automixing Aux. Data
2 Expansion Signals
26 Automixing Control Data
DTMF
Generator
0 dBu
TEL
Output
Processing
Aux
Output
Processing
DM1624 Master
DM1624
Sl
av
e
1
24
Outputs
DM1624 Master
with
DM1624 and DMTH4 Slaves
DM1624 Master
DM1612
Sl
av
e
1
24
1
12
Master and
Slave Outputs
Outputs
DM1624 Master
with
DM1612 and DMTH4 Slaves
12
13 Master only
Outputs
DM1612 Master
DM812 Sl
av
e
1
1
12
Outputs
DM1612 Master
with
DM812 and DMTH4 Slaves
12
Outputs
1
Outputs
12
Outputs
1(13)
12(24)
DMTH4 Sl
av
e
Codec
AUX
Outputs
TEL
DMTH4 Sla
ve
Codec
AUX
Outputs
TEL
DMTH4 Sla
ve
Codec
AUX
Outputs
TEL
DM Series Back Propogation Diagram